The diagnostic accuracy of non-imaging screening protocols for vestibular schwannoma in patients with asymmetrical hearing loss and/or unilateral audiovestibular dysfunction: a diagnostic review and meta-analysis

Background: Currently, all patients presenting with asymmetrical sensorineural hearing loss and/or unilateral audiovestibular dysfunction (i.e. tinnitus, dizziness) undergo MRI, leading to a substantial amount of MRIs with negative findings as the incidence of vestibular schwannoma (VS) in this screening population varies between 1% and 4.7% (i.e. more than 95% of MRIs are negative for VS).

Objective of review: The aim was to assess the diagnostic accuracy of different non-imaging screening protocols that can be used prior to MRI to select patients at high risk of VS.

Type of review: Diagnostic review and meta-analysis.

Search strategy: We systematically searched MEDLINE, Embase and The Cochrane Library as from inception up to 28 July 2016. We included studies that compared non-imaging screening protocols to MRI as gold reference standard.

Evaluation method: Methodological quality was assessed by two independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies tool. Data necessary to complete 2 × 2 tables were obtained, and patient, study, screening and imaging characteristics were extracted. We calculated sensitivity and specificity of all tests and obtained pooled estimates using a bivariate random effects model.

Results: We analysed 12 studies (4969 patients) of poor to moderate quality according to the quality assessment. Most studies tested diagnostic accuracy of multiple screening protocols. Five pure-tone audiometry (PTA) protocols were studied by multiple authors; pooled estimates for sensitivity ranged from 88% [95% CI: 84-91] to 91% [95% CI: 52-99] and specificity from 31% [95% CI: 10-66] to 58% [95% CI: 49-65]. Due to heterogeneity, we were unable to pool other tests. In five studies testing auditory brainstem response, sensitivity values ranged from 37% [95% CI: 23-52] to 100% [95% CI: 40-100] and specificity from 57% to 96% [95% CI: 87-100]. Two authors studied PTA shape as a screening test. Presenting symptoms, electronystagmography, caloric irrigation and hyperventilation test were assessed by one study each. All reported low diagnostic accuracy.

Conclusions: All identified studies had a moderate-to-high risk of bias, and none of the currently available non-imaging screening protocols appear to be accurate in detecting VSs.